I've got a 1997 F700 bucket truck with a 429 Gasoline (was swapped over before we bought the truck from liquid propane) that we're having issues with. She sputters and backfires from a stop until around 1700 RPM's seems like when she warms up it doesn't do this as much. Seems like when we pump the pedal it helps get it goin better. While driving it home from a jobsite it started doing the sputter/backfire thing on the highway at normal speeds and I had to pump the pedal almost all the way home, but it went back to normal about 10 miles from home. Oh, and when it went back to normal it the tranny shifted into next gear (she was in third gear half the way home).

our problem actually started a month ago when the truck ran outta gas then wouldn't start back up. we had a mechanic take a look at it. he changed the distributor, and she's been runnin rough ever since. My thought is that he stabbed the distributor in wrong and she needs timed. we cant find any timing marks on the pulleys however.

I guess what I'm looking for is the correct timing specs for the vehicle. also, seems like a sensor prob of some type to me due to the fact that it normally goes away after warm-up. could it be a throttle sensor as well ? this problem has us completely stumped and we need to get her back up and runnin as she is our made work vehicle and source of income.

any help would be appreciated greatly!!!!

 

don't have the specs but i have the same situation with my 84 the timing has to be right on. seems like the coolant temp sensor ties in with the elect advance of the distributer. advance or retard it a little and you should instantly notice a difference. hope that helps a little. almost feels like you are riding the brake until it really warms up?

 

sounds like the same prob cause im havin a temp prob when it sits runnin too long, but we think that is due to the fan clutch